There have been patented and manufactured ever increasing numbers of inexpensive slant-support display easels in recent years.
Basically these consist of a means for positioning a slanting display or writing surface having easel support means. Usually the structure incorporates one or more vertical panels for displaying advertisements, slogans, logos, calendars or the like.
Unlike wall-mounted display structures which can be attached to a solid vertical supporting surface and hence can be readily used as a writing surface, the slant-mount easels must be able to provide adequate support by their own inherent structural details, when slidably or loosely placed upon a planar support surface, such as a desk or counter top, so as to bear the pressure of writing thereon.
In the past most of the art pertaining to such structures have been formed of relatively thick, substantially inflexible cardboard stock, with or without plastic facing layers. Such structures generally use a relatively complex tongue and slot means to maintain the easel in operative position and rely on the strength of the materials and their thickness to provide stability during use.
Economy makes essential structures which may be shipped in a substantially flat form and thereafter have the easel mount moved into operative position.
Illustrative of such prior art are the following patents:
U.S. Pat. No. 2,355,706 to Cross
U.S. Pat. No. 2,750,698 to Nichols
U.S. Pat. No. 3,787,853 to Nichols
U.S. Pat. No. 2,798,322 to Nichols
U.S. Pat. No. 2,825,516 to Cross
U.S. Pat. No. 2,831,285 to Cross
U.S. Pat. No. *2,916,242 to Cross et al
U.S. Pat. No. 2,926,441 to Cross
U.S. Pat. No. *2,954,625 to Nichols
U.S. Pat. No. 2,958,968 to Nichols
U.S. Pat. No. 2,960,783 to Nichols
U.S. Pat. No. 3,021,631 to Cross
U.S. Pat. No. 3,067,652 to Cross
U.S. Pat. No. 3,068,139 to Cross
U.S. Pat. No. *3,305,206 to Nichols
U.S. Pat. No. *3,580,536 to Nichols
Of the above, while all are easel mounted, the most pertinent are those marked with an asterisk, in that the structures disclosed therein have the slanting display support surface positioned at a small acute angle relative to their planar supporting environment, because such articles are more easy to use as writing and display surfaces. However, this very property of facile use causes a requirement of an ability by such structures to withstand greater and more frequently applied writing pressure.
While in theory this art problem could be solved by a choice of thick, strong material, such articles are generally used as giveaway promotional calendars, desk memo pads and the like, and hence must be inexpensive. The cost of sufficiently thick rigid structures to provide such proper easel mounts has become intolerable from a marketing standpoint.
Therefore, the art has turned to a search for new structures which can be manufactured with a minimum number of steps and still provide an erectable rigid satisfactory structure using thin, inexpensive materials.
The present invention accomplishes these desired results by novel means which rely on the snap locking of thin materials into operative slant-support mounts by structures more simple, more inexpensive and more strong than the structures described and claimed in the above asterisked patents. Thus, Cross et al. U.S. Pat. No. 2,916,242 uses a plurality of multiple, relatively thick cardboard or the like layers hingedly connected panels with a slot and tongue snap-locking means whose cost is much greater than that of the present invention. Nichols U.S. Pat. No. 2,954,625 is similarly prohibitively expensive. This patent is also illustrative of a further difficulty of using such slant-top easel display mounts; where a tongue and slot connection is used with thick cardboard or the like, repeated locking and unlocking causes the material to become dog-eared or frayed and to lose resiliency at the coacting locking means.
In Nichols U.S. Pat. No. 3,305,206 the structures rely upon an abutment layer to tension the easel in operative position and this requires a substantial, expensive thickness, or the panels will not be maintained in their snap-lock original positions, because there will will not then be an effective snap-lock operative position attainable with thin layered materials which lack both rigidity and sufficient the requisite edge abutment stops. Similar problems are presented by the structures of Nichols U.S. Pat. No. 3,580,536 since the materials which must be used therein require inherent rigidity and resistance to flexure during snap-lock erection and during use, in order to be operative.
This causes a locking tension which will be variable with continued use as well as relatively thick expensive materials.
Also, all of these prior art structures require pre-shaping or pre-stitching of a memo or calendar pad to the slant support surface, since this joining operation cannot be performed after flats are printed and folded for shipment.
It is to be noted that the ability to use the inherent resiliency of paperboard or the like has been long recognized and used, as shown in Larkin U.S. Pat. No. 1,990,739, but this resiliency cannot be maintained uniform during operation, because such properties have changed during repeated use by the prior art devices.
It is therefore the principal object of this invention to provide thin inexpensive material to form snap-lock slant board easels having greater tension, longer lasting uniform tension, and readily preselectable tension to cause retention of the snap lock mount structure, while enabling manufacture with a single stapling step which can be performed after the panels are completely printed and folded-over.
It is a further object to eliminate the use of glue or adhesive to maintain tension of panel to panel positioning to eliminate the gradual debilitating effect of the passage of time on all adhesive joints.
The combined simplicity and rigidity of the thin layered slant board supports of the invention will be more readily appreciated by reference to the accompanying figures of the drawing and to the detailed description and appended claims.